1. Field of the Invention
The present invention relates to a so-called xe2x80x9cpan framexe2x80x9d of seat cushion for use with a vehicle seat, and in particular, to the structure of seat-cushion pan frame which is formed by a press working from a rigid plate material, such as a steel sheet.
2. Description of Prior Art
A typical seat cushion of a vehicle or automotive seat is generally composed of an elastic padding and a covering material affixed thereon, with a seat cushion frame provided for supportive receipt of the elastic padding. In most cases, the covering material is attached over a unit of the padding and seat cushion frame in an integral manner, thus presenting one integrated appearance of seat cushion.
Among various kinds of frameworks for the seat cushion, known is the so-called xe2x80x9cpan framexe2x80x9d which is one unitary frame formed in a pan-like configuration by press working from a rigid material or a seat steal for instance. This seat-cushion pan frame is normally fixed on the floor of vehicle or automobile via securing members. In general, the pan frame has two securing areas in pairs therein, which are fixed via securing bolts to a corresponding one of a pair of slide rails (as at (SL) in FIG. 2) fixed on the floor.
Such seat-cushion pan frame is supported only at those securing points on the floor, slide rail or the like, which means that a load from an occupant thereon will be intensively exerted on the securing points, such as securing holes in the frame and the bolts. Over a lengthy period of its use with an automotive seat, the pan frame receives a continued load and vibrations from the occupant and automobile for a long mileage of driving, resulting in a considerable wear or metal fatigue in the frame. As a result, it is possible that the frame will be deformed, causing an unstable poor seating touch of the seat cushion as a whole, and further, the less stiff areas of the frame, i.e. the securing holes of frame through which the securing bolts pass, will become lower in strength, and, in the worst case, the peripheral regions of each securing hole might be broken and cracked.
Conventionally, to solve that problem, provision of reinforcing members to the whole pan frame or to the securing holes of the frame and increase of the frame thickness for that purpose have been proposed and effected to avoid the lowered strength of the frame and local areas adjacent the securing holes. However, such provision of reinforcing members has led to increase of fitting parts and intricate structure of the frame, while the thickened frame has encountered the increased size and weight of frame itself. Those hitherto breakthroughs are found hardly acceptable cost-wise and in assembly of the frame.
In view of the above-stated drawbacks, it is a main purpose of the present invention to provide an improved structure of seat-cushion pan frame for use with a seat back of a vehicle seat, which is of a much simplified structure adaptable for easy use with the seat back, while effectively reinforcing the pan frame itself by dispersing a load applied to the frame toward securing areas of the pan frame.
To attain such purpose, according to the present invention, in a seat-cushion pan frame wherein its securing areas are distributed therein in a mutually spaced-apart manner and adapted to be secured to a side of floor of the vehicle seat, the structure of this particular frame basically comprises:
a bottom wall defined in the seat-cushion pan frame; and
a reinforcing pattern so press formed in the bottom wall during a press working process as to protrude therefrom, with a flat bottom region defined therein;
the reinforcing pattern being arranged in the bottom wall such as to communicate with the foregoing securing areas.
Accordingly, since such integral reinforcing pattern is relatively large in width due to the formation of flat bottom region therein and also communicates with the securing areas, a load applied to the pan frame will be dispersed and absorbed by the reinforcing pattern, so that a weakened load will be immediately transmitted towards the securing areas and escaped therefrom to the outside of pan frame, e.g. the floor of vehicle or automobile. Preferably, the reinforcing pattern may comprise a generally X-shaped reinforcing channel having its four channel sections, such that each of the four channel sections has a flat bottom region defined therein and therealong, and extends to the securing areas in communication therewith.
It is a second purpose of the present invention to positively reinforce the afore-said securing areas of the pan frame in addition to the above-discussed structure.
For that purpose, in accordance with the present invention, the structure of seat-cushion pan frame may basically comprise:
(a) a bottom wall defined in the seat-cushion pan frame, said bottom wall having a right surface side inwardly of the seat-cushion pan frame and a reverse surface side outwardly thereof;
(b) a primary reinforcing pattern so press formed in the bottom wall during the press working process as to protrude therefrom with a flat bottom region defined therein, the reinforcing pattern being arranged in the bottom wall such as to communicate with the securing areas; and
(c) an auxiliary reinforcing pattern so pressed formed in the primary reinforcing pattern during the press working process as to protrude from a plane at which there lies the foregoing right surface side of said bottom wall, and surround each of said securing areas.
Accordingly, the provision of such auxiliary reinforcing pattern is effective in surrounding and isolating the securing areas from other areas of the pan frame including the primary reinforcing pattern, whereupon a load applied to the pan frame is blocked by the auxiliary reinforcing pattern against transmission to the securing areas and will be changed thereby in direction so that it is smoothly escaped to the outside of pan frame.
Other advantages and features of the present invention will become apparent from reading of the description hereinafter, with reference to the drawings.